Detachable easel with keyboard tray and wireless pairing protocol

ABSTRACT

According to one embodiment, a detachable easel is provided for supporting a portable electronic device in a substantially upright position at a desired viewing angle when the easel is in an open position, and for stowing a wireless keyboard module onto a back surface of the portable electronic device when the easel is in a closed position. In one preferred embodiment, the detachable easel consists of a 3-bar linkage mechanism comprising a first link configured to provide a retaining frame for magnetically adhering to a back surface of the portable electronic device, a second link configured to provide a support frame for supporting the portable electronic device at a number of different viewing angles when the easel is in the open position, and a third link configured to provide a keyboard tray for stowing the wireless keyboard module onto the back surface of the portable electronic device when the easel is in a closed position.

PRIORITY CLAIM

The present application claims priority to U.S. Provisional ApplicationNo. 61/969,616 filed Mar. 24, 2014.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to the field of portableelectronic devices and, more particularly, to a portable electronicdevice, detachable easel with keyboard tray, wireless keyboard andmethod for communicating a charging signal and a pairing code between aportable electronic device and a wireless keyboard upon establishingphysical contact between the two.

2. Description of the Related Art

The following descriptions and examples are not admitted to be prior artby virtue of their inclusion within this section.

Tablet personal computers (PCs) have become increasingly more popular,as the trend for highly compact, highly powerful computing devicescontinues. The tablet PC (or simply “tablet”) is a fully functionalpersonal computer with a full operating system, which is capable ofrunning familiar productivity applications (such as Microsoft's Office™applications), and offers the same rich connectivity to the Internetthat a desktop or notebook PC provides.

The tablet is designed to work well with all types of input devices,including keyboards, styluses, and even a user's finger. The tablettypically includes a resistive or capacitive-based touch screen forreceiving input from a stylus or finger, and provides effectivehandwriting recognition software for recognizing such input ashandwritten text. In many cases, a virtual keyboard or graphical userinterface (GUI) may be displayed on the touch screen for receiving inputfrom the user. For longer documents and other applications, however, aperipheral keyboard device may provide the most efficient means for datainput.

Unfortunately, using a peripheral keyboard requires the tablet user tocarry the keyboard while moving from place to place. The need to carryalong the keyboard, however small or compact, reduces the advantages ofusing a tablet. If a peripheral keyboard is to be used with the tablet,the user also needs a practical way to view the tablet display screenwhile entering data with the keyboard. This typically involves the use astand to support the tablet in the desired viewing angle. Therefore, notonly is the user required to carry a separate keyboard, but also aseparate stand for supporting the tablet screen while the user's handsengage the keyboard. Accordingly, a need exists for an efficient way topermit a tablet user to input data into the tablet via a keyboard,without the need to carry a separate keyboard and a separate stand alongwith the tablet.

There are many different types of wired and wireless keyboards known inthe art for use with portable electronic devices. Wireless keyboardshave become increasingly popular, as their cord-free status providesmore freedom of movement and cleaner workspaces. In most cases, wirelesskeyboards may connect with host devices (e.g. personal computers,portable electronic devices and workstations) via a wirelesscommunication technology, such as optical or radio frequency (RF). RFtechnology allows wireless communications between peripheral devices andhost devices without requiring alignment of the devices or a path freeof obstructions between the devices. There are several RF communicationprotocols known in the art, including Bluetooth, Wi-Fi, andUltra-Wideband (UWB) to name just a few.

A pairing protocol is used to establish a wireless communication channelbetween a wireless keyboard (or another wireless peripheral device) anda host device (e.g., a tablet PC). The wireless keyboard may be “paired”with a host device by entering a PIN into both devices, or bybroadcasting a shared key. Once the devices are successfully paired,they can communicate with each other over the wireless communicationchannel. However, in some environments having a large pool of wirelesskeyboards and tablets, it is easy for the wireless keyboards and tabletsto become mismatched. When this occurs, it is often necessary to repeatthe pairing process to reestablish wireless communication between thetwo devices.

Security is important for those using peripheral devices to entersensitive data into a host system, such as passwords or account numbers.However, current RF communication protocols fail to provide a simplepairing protocol to establish a secure communication channel betweenperipheral and host devices, without requiring significant userinteraction or a security key exchange over public airspace. Using thepublic airspace to broadcast a pairing request and to exchange securityinformation is prone to various security breaches. For instance, aneavesdropper may try to intercept a radio transmission containing asecurity key.

In some cases, encryption may be used in order to protect sensitiveinformation. Encryption is the process of encoding information in such away that only the person (or computer) with the encryption key, a codethat the devices use to encrypt or decrypt a packet of information thatis transmitted to or from a device, can decipher the information. Theuse of encryption to facilitate secure communication between a wirelessperipheral device and a host device requires both devices to be equippedwith the same encryption key. A private key, or symmetric key, is anencryption/decryption key known only to the party or parties thatexchange encrypted communications. Generally, systems that currentlyemploy private key encryption technology require the person pairing thedevices to manually pass the encryption key from one device to theother. This requires the user to interact with the software on the hostdevice and typically involves a number of manual steps, such asinputting the key manually. A need, therefore, exists for an improvedmethod for simplifying and securing the connection and pairing processbetween a wireless keyboard and a tablet.

SUMMARY OF THE INVENTION

The present invention overcomes the limitations of the prior art byproviding a portable electronic device (e.g., a tablet PC), a detachableeasel with a keyboard tray, a wireless keyboard module and a method forcharging and automatically pairing a wireless keyboard with a portableelectronic device upon establishing physical contact between the two.The following description of various embodiments of the invention is notto be construed in any way as limiting the subject matter of theappended claims.

According to one embodiment, a detachable easel is provided forsupporting a portable electronic device in a substantially uprightposition at a desired viewing angle when the easel is in an openposition, and for stowing a wireless keyboard module onto a back surfaceof the portable electronic device when the easel is in a closedposition. In one preferred embodiment, the detachable easel consists ofa 3-bar linkage mechanism comprising a first link, a second link havinga distal end connected to a first distal end of the first link via afirst pair of axial hinges, and a third link having a distal endconnected to a second distal end of the first link via a second pair ofaxial hinges (i.e., the first link is coupled between the second andthird links via axial hinges located at the distal ends of the firstlink).

The first link is configured to provide a retaining frame formagnetically adhering to and supporting a back surface of the portableelectronic device. For example, the first link may comprise one or moremagnetic structures for aligning with and magnetically adhering tocorresponding magnetic structures located on the back surface of theportable electronic device.

The second link is configured to provide a support frame for supportingthe portable electronic device at a number of different viewing angleswhen the easel is in the open position. In one preferred embodiment, thesecond link comprises a pair of slots, wherein each slot is configuredfor receiving and guiding a peg (connected to the third link) to alocation along the slot that supports the portable electronic device ina substantially upright position at a desired viewing angle. In someembodiments, the pair of slots may each have notches for providing afinite number of viewing angles. In other embodiments, the pair of slotsmay be configured to provide a substantially infinite number of viewingangles within a range of motion. In other embodiments, the pair of slotsmay be configured for providing one fixed viewing angle. In someembodiments, the second link may comprise one or more magneticstructures to provide a latching force, which helps to retain thedetachable easel in the closed position.

The third link is configured to provide a keyboard tray for stowing thewireless keyboard module onto the back surface of the portableelectronic device when the easel is in a closed position. When the easelis opened, the third link presents the wireless keyboard module to theuser in a way that enables the user to grasp and extract the module inan ergonomic manner. According to one embodiment, the third link may beselectively positioned at an angle with respect to the first link over apredefined range of motion. For example, the angle may selected from agroup consisting of about 0° to about 45°, or more preferably, from agroup consisting of about 0° to about 25°. According to anotherembodiment, the third link may be positioned at a fixed angle withrespect to the first link when the detachable easel is in the openposition.

According to one embodiment, the first link may comprise twosubstantially vertical members, each coupled at one end to a differentone of the first pair of axial hinges and coupled at another end to asubstantially horizontal member of the first link. The two substantiallyvertical members of the first link may comprise one or more magneticstructures, which are configured for aligning with and magneticallyadhering to corresponding magnetic structures on the back surface of theportable electronic device.

The second link may also comprise two substantially vertical members,each coupled at one end to a different one of the first pair of axialhinges and coupled at another end to a substantially horizontal memberof the second link. The substantially horizontal member of the secondlink may be configured for resting upon a support surface when thedetachable easel is in the open position. When the detachable easel isin the closed position, the two substantially vertical members of thesecond link may be configured to align with and receive the twosubstantially vertical members of the first link. In some cases, the twosubstantially vertical members of the second link may comprise one ormore magnetic structures for providing a latching force, which helps toretain the detachable easel in the closed position.

The third link is slidably connected to the second link fortransitioning the detachable easel from the closed position to the openposition and vice versa. According to on embodiment, a width of thethird link may be less than a distance separating the two substantiallyvertical members of the second link, such that when transitioning thedetachable easel from the closed position to the open position, thethird link slides between the two substantially vertical members of thesecond link along a longitudinal axis of the two substantially verticalmembers.

According to one embodiment, a wireless keyboard module is provided foruse with a portable electronic device. The wireless keyboard moduledescribed herein comprises a wired connector, which is configured toelectrically connect to a wired connector on a back surface of theportable electronic device. Once connected, the wired connectors of thewireless keyboard module and the portable electronic device areadvantageously configured to pass a charging signal and a pairing codethere between. For example, the wireless keyboard module may include abattery and a charging circuit, which is coupled for charging thebattery upon receiving the charging signal from the portable electronicdevice via the wired connectors. The wireless keyboard module mayfurther include a microcontroller configured to automatically initiateand run a pairing subroutine once the wired connectors of the wirelesskeyboard module and the portable electronic device are connected. Thepairing subroutine may cause a pairing code to be passed from thewireless keyboard module to the portable electronic device via the wiredconnectors. The pairing subroutine may generate a different pairing codeevery time the wired connectors are connected.

In some embodiments, the wireless keyboard module may further includeone or more thermal intake vents that allow air to pass through thekeyboard module into the portable electronic device when the keyboardmodule is mounted onto the back surface of the portable electronicdevice. The thermal intake vent(s) enable the portable electronic deviceto more effectively control its internal and external temperatures. Thethermal intake vent(s) may be placed substantially anywhere around theperiphery of the keyboard, but are preferably placed near correspondingair vents located on the back surface of the portable electronic device.If the air vents are not co-located, the spaces between keys may providesufficient air flow channels for passing air to/from the portableelectronic device.

According to another embodiment, a portable electronic device isprovided herein and configured to communicate with a wireless keyboardmodule. The portable electronic device described herein comprises awired connector, which is configured to electrically connect to a wiredconnector of the wireless keyboard module when the wireless keyboardmodule is retained on a back surface of the portable electronic device.

In one preferred embodiment, the wireless keyboard module may beretained on the back surface of the portable electronic device throughthe use of a detachable easel, as described herein. In such anembodiment, one or more magnetic structures may be arranged on the backsurface of the portable electronic device for aligning with andmagnetically adhering to corresponding magnetic structures on thedetachable easel. In addition to retaining the wireless keyboard moduleon the back surface of the portable electronic device, the magneticstructures on the portable electronic device and the detachable easelmay help with the alignment and connection of the wired connector of thewireless keyboard module to the wired connector on the portableelectronic device when the easel is closed.

When physically and electrically connected, the wired connectors of thewireless keyboard module and the portable electronic device areconfigured to pass a charging signal and a pairing code there between.For example, the portable electronic device may include interfacecircuitry for receiving a keyboard docked signal when the wiredconnectors of the wireless keyboard module and the portable electronicdevice are connected, and in response to the keyboard docked signal,supplying a charging signal to the wireless keyboard module via thewired connectors. The charging signal may be used to charge a batteryincluded within the wireless keyboard module, as described herein. Theportable electronic device may also include firmware for receiving apairing code from the wireless keyboard module via the wired connectors.If pairing is successful, the portable electronic device may communicatewith the wireless keyboard module via RF circuitry and antennas when thewired connectors of the wireless keyboard module and the portableelectronic device are disconnected.

According to another embodiment, a method is provided herein forcharging a wireless keyboard module and pairing the wireless keyboardmodule to a portable electronic device. In general, the method may beginby physically and electrically connecting a wired connector of thewireless keyboard module to a wired connector located on a back surfaceof the portable electronic device. Once the wired connectors areconnected, a charging signal may be passed from the portable electronicdevice to the wireless keyboard module via the wired connectors. Apairing code may also be passed from the wireless keyboard module to theportable electronic device via the wired connectors when connected.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages of the present invention may become apparent to thoseskilled in the art with the benefit of the following detaileddescription of the preferred embodiments and upon reference to theaccompanying drawings in which:

FIG. 1 is a back-side view of a portable electronic device (e.g., atable PC), according to one embodiment.

FIG. 2 is a front-side view of a detachable easel with stowed keyboardmodule in a closed position.

FIG. 3 is a back-side view of the detachable easel and stowed keyboardmodule shown in FIG. 2 mounted onto the back surface of the portableelectronic device shown in FIG. 1.

FIG. 4 is a side view of the portable electronic device and detachableeasel with keyboard module shown in FIG. 3.

FIG. 5 is a side view of the portable electronic device with thedetachable easel (without keyboard module) mounted to the back surfacethereof and opened in a screen viewing angle.

FIG. 6A is a back-side view of the portable electronic device anddetachable easel shown in FIG. 5, according to one embodiment.

FIG. 6B is a back-side view of the portable electronic device anddetachable easel shown in FIG. 5, according to another embodiment.

FIG. 7 is a side view of the portable electronic device and detachableeasel, illustrating how the wireless keyboard module may be easilystowed in the keyboard tray portion of the easel, or removed therefrom,when the detachable easel is opened in the screen viewing angle.

FIG. 8 is a block diagram of various circuitry within the portableelectronic device (e.g., a table PC) and wireless keyboard module andthe wired connectors that, once connected, pass a charging signal and apairing code between the portable electronic device and the wirelesskeyboard module.

FIG. 9 is a flow chart diagram illustrating one embodiment of a methodfor charging and automatically pairing a wireless keyboard with aportable electronic device upon physically connecting a wired connectorof the keyboard module to a wired connector of the portable electronicdevice.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and may herein be described in detail. Thedrawings may not be to scale. It should be understood, however, that thedrawings and detailed description thereto are not intended to limit theinvention to the particular form disclosed, but on the contrary, theintention is to cover all modifications, equivalents and alternativesfalling within the spirit and scope of the present invention as definedby the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to one embodiment, the present invention is directed to aportable electronic device and a detachable easel, which can store awireless keyboard module on the backside surface of the portableelectronic device when the keyboard is not in use, and support theportable electronic device in an upright manner, so that the devicedisplay screen is ergonomically angled towards the user. The presentinvention is particularly well suited to tablet PCs, but could be usedwith other portable electronic devices that have touch sensitive displayscreens, and would benefit from the use of a wireless keyboard device.As the touch sensitive display screen (or simply “touch screen”) isoften the primary means of data input in such devices, it would bedesirable to seamlessly integrate the wireless keyboard module with thetablet when not in use. FIGS. 1-6 illustrate one preferred embodiment ofa portable electronic device and a detachable easel with a seamlesslyintegrated wireless keyboard module.

FIG. 1 is a back-side view of a portable electronic device 10 and FIG. 2is a front-side view of a detachable easel 20 with a stowed keyboardmodule 30 in the closed position. In particular, FIG. 1 illustrates aback surface 12 of the portable electronic device 10 having magneticstructures 14 configured for aligning and magnetically connecting tomagnetic structures 28 on the front surface of the detachable easel 20shown in FIG. 2. As used herein, a “magnetic structure” is a structurethat either generates a magnetic field, or is susceptible to a magneticfield. For example, a magnetic structure may be a raised or embeddedmagnet, a metal foot or protrusion, or a metal-lined cavity.

Any combination of magnet structures 14/28 may be used on the backsurface of the portable electronic device 10 and on the front surface ofthe detachable easel 20. For example, two of the magnetic structures 14on the back surface 12 of the portable electronic device 10 may beimplemented with metal feet, while the other two are implemented withraised magnets. Alternatively, an all-magnet or all-metal feetembodiment is envisioned for the back surface 12 of the portableelectronic device 10. The purpose of the magnetic structures 14 is toalign with and magnetically connect to corresponding magnetic structures28 (e.g., metallic cavities or embedded magnets) positioned on the frontsurface of the detachable easel 20. The strength of the magnetic bondmay generally depend on the number and size of magnets used on theportable electronic device 10 and/or the detachable easel 20, and shouldbe chosen to provide a secure means for adhering the easel to the backof the portable electronic device.

FIGS. 1-2 illustrate the detachable easel 20 and keyboard module 30separated from the portable electronic device 10. FIGS. 3-4 illustratethe detachable easel 20 and keyboard module 30 magnetically stowed ontothe back surface 12 of the portable electronic device. As shown in FIGS.3-4, the detachable easel 20 and keyboard module 30 seamlessly integratewith each other and with the portable electronic device 10 when thekeyboard is not in use. Such seamless integration enables the user tointeract with the touch screen 18 (FIG. 4) of the portable electronicdevice 10, and provides secure keyboard storage when the keyboard is notin use, while giving the appearance of a single monolithic device. Insome embodiments, the detachable easel 20 and/or the keyboard module 30may be implemented with a non-slip back-side surface 32 to providebetter grip and a more stable horizontal support surface.

As shown in the embodiment of FIG. 2 (and later in FIG. 8), keyboardmodule 30 may generally comprise a QWERTY keyboard 46 and a touch pad(TP) 48 for accepting user input. Although the touch pad 48 ispositioned below the keyboard 46 in FIG. 2, alternative arrangements maybe used without departing from the scope of the invention. In somecases, other means for accepting user input may be used in addition to,or in place of, touch pad 48.

Keyboard module 30 is a wireless keyboard module that is generallyconfigured to connect with one or more host devices (e.g. personalcomputers, portable electronic devices, workstations, etc.) via awireless communication technology, such as an optical or radio frequency(RF) technology. In many cases, RF communication may be preferred, as itallows wireless communications between peripheral devices and hostdevices without requiring alignment of the devices or a path free ofobstructions between the devices. There are several RF communicationprotocols known in the art, including Bluetooth, Wi-Fi, andUltra-Wideband (UWB), with which the wireless keyboard module 30 may useto communicate with a host device. However, wireless keyboard module 30is not strictly limited to RF communication protocols, and mayalternatively use any other wireless communication technology known inthe art.

Wireless keyboard module 30 provides numerous advantages overconventional wireless keyboard designs. As shown in FIG. 3, for example,the wireless keyboard module 30 includes at least one thermal intakevent 34 on the back-side of the module that allows air to pass throughthe keyboard into the portable electronic device 10. The thermal intakevent(s) 34 enable the portable electronic device 10 to more effectivelycontrol its internal and external temperatures. Although illustrated onthe top of the keyboard module, the thermal intake vent(s) 34 may beplaced substantially anywhere around the periphery of the keyboard,preferably near corresponding air vents (e.g., air vent 17, FIG. 1)located on the back surface 12 of the portable electronic device 10. Ifthe air vents 34/17 are not co-located, the spaces between keys onkeyboard module 30 may provide sufficient air flow channels for passingair to/from the portable electronic device 10.

As another unique feature, a wired connector 36 is provided on the frontsurface (see, FIG. 2) of the wireless keyboard module 30 for aligningwith and connecting to a corresponding wired connector 16 on the backsurface 12 of the portable electronic device 10 (see, FIG. 1) when thewireless keyboard module 30 is properly stowed in the detachable easel20 and magnetically connected to the portable electronic device (see,FIGS. 3-4). The magnetic structures 14 on the back surface 12 of theportable electronic device and the corresponding magnetic structures 28on the front surface of the detachable easel 20 may assist in thealignment of the wired connectors 36 and 16. In one embodiment, thewired connectors 36/16 may be water-resistant, blind mating pogo pinconnectors, although other types of connectors, such as pinlessconnectors, may be used. As described in more detail below, wiredconnectors 36/16 are preferably configured to pass both digital pairingcodes and charging voltages between the portable electronic device 10and the wireless keyboard module 30 when the keyboard module ismagnetically stowed on the back surface 12 of the portable electronicdevice 10. A keyboard module 30 that can be charged by a portableelectronic device 10, and automatically paired with the portableelectronic device upon contact, represent further advantages overconventional wireless keyboard designs.

When a user wishes to place the portable electronic device 10 in theupright position, it is desirable to support the device 10 in anergonomic position that enables the user to use the touch screen 18 andview the screen at a desirable viewing angle. There are many differenttypes of stands and supports currently on the market for this purpose.For example, some conventional portable electronic devices come equippedwith an integrated kickstand or easel that pops out of the rear of thedevice to support the device in a display mode. Although a wirelesskeyboard can be used with these devices, they provide no means forseamlessly and securely stowing the keyboard on the device. Otherexamples include keyboard docking stations and electronic device coverswith integrated keyboards, which are sold as accessories to portableelectronic devices. These either use a kickstand like mechanism, orsimply an angled docking receptor, to support the portable electronicdevice at a fixed viewing angle. These designs also fail to providemeans for seamlessly and securely stowing a keyboard on the back of theportable electronic device.

The detachable easel 20 shown in FIGS. 1-6 improves upon conventionalstands, supports and covers in a variety of ways. As noted above, thedetachable easel 20 provides means for seamlessly and securely stowing akeyboard on the back surface 12 of the portable electronic device 10,while providing the look and feel of a single piece of equipment. Themagnetic structures 14 on the portable electronic device 10 and thecorresponding magnetic structures 28 on the detachable easel 20 providea strong magnetic bond that retains the detachable easel 20 on the backsurface 12 of the device 10, and provides a latching force to keep theeasel in the closed position until opened by the user. Additionaladvantages of the detachable easel 20 are described below.

FIGS. 5-7 show the detachable easel 20 mounted onto the back surface ofthe portable electronic device 10 and arranged in the open position. Asshown in FIGS. 5-7, the detachable easel 20 is preferably implemented asa 3-bar linkage mechanism, wherein a first “link” provides a retainingframe 21 for magnetically adhering to and supporting the back surface 12of the portable electronic device 10, a second “link” provides ansupport frame 22 for supporting the device 10 at a number of differentviewing angles when the detachable easel is in an open position, and athird “link” provides a keyboard tray 23 for stowing the wirelesskeyboard module 30. As described below, the 3-bar linkage mechanismenables the portable electronic device 10 to be supported in anergonomic position that allows the user to use the touch screen 18 andview the screen at a number of different viewing angles.

As shown most clearly in FIG. 5, the retaining frame (first link) 21includes a first pair of axial hinges 24 at a first distal end of theretaining frame for connecting to distal ends of the support frame(second link) 22 and providing rotational motion about the hinges.Another pair of axial hinges 25 is provided at the other distal end ofthe retaining frame 21 for connecting to distal ends of the keyboardtray (third link) 23 and providing rotational motion about the hinges.Rotation about hinges 24 and 25 enables the detachable easel 20 to betransitioned from the closed position shown in FIGS. 2-4 to the openposition shown in FIGS. 5-7.

As shown most clearly in FIGS. 6A and 6B, the retaining frame (firstlink) 21 includes two substantially vertical members 21 a, each coupledat one end to a different one of the first pair of axial hinges 24 andcoupled at another end to a substantially horizontal member 21 b of theretaining frame 21. The two substantially vertical members 21 a of theretaining frame 21 preferably include one or more magnetic structures28, which are configured for aligning with and magnetically adhering tocorresponding magnetic structures 14 on the back surface 12 of theportable electronic device 10 (FIG. 1).

The support frame (second link) 22 also includes two substantiallyvertical members 22 a, each coupled at one end to a different one of thefirst pair of axial hinges 24 and coupled at another end to asubstantially horizontal member 22 b of the support frame 22. The twosubstantially vertical members 22 a of the support frame 22 arepreferably configured to align with and receive the two substantiallyvertical members 21 a of the retaining frame 21 when the detachableeasel 20 is in the closed position (FIGS. 2-4). When the detachableeasel 20 is in the open position (FIGS. 5-7), the substantiallyhorizontal member 22 b of the support frame 22 may rest on a supportsurface, such as a table or desk. In some embodiments, one or moremagnetic structures 28 may also be placed on the two substantiallyvertical members 22 a of the support frame 22 to provide a latchingforce, which helps retain the detachable easel 20 in the closedposition. In some embodiments, it may be desirable to position themagnetic structures 28 included on the support frame 22 so that theyalign with the magnetic structures 28 and 14 included on the retainingframe 21 and on the back surface 12 of the portable electronic device10, so that the same magnetic structures that secure the easel to theelectronic device may also be used to provide a latching force to holdthe easel in the closed position.

In the embodiment shown in FIG. 6A, the keyboard tray (third link) 23includes two substantially vertical members 23 a, each coupled at oneend to a different one of the second pair of axial hinges 25. A shelf 23b is provided at the other end of the vertical members 23 a forsupporting a top portion of the keyboard module 30. Side portions of thekeyboard module 30 may be supported by the vertical members 23 a. In theembodiment shown in FIG. 6B, the keyboard tray (third link) 23 includesa continuous surface for supporting the keyboard module 30.

The keyboard tray (third link) 23 is slidably connected to the supportframe (second link) 22 for transitioning the detachable easel 20 fromthe closed position (FIGS. 2-4) to the open position (FIGS. 5-7) andvice versa. In preferred embodiments, a width of the keyboard tray 23 isless than a distance separating the two substantially vertical members22 a of the support frame 22, such that when transitioning thedetachable easel 20 from the closed position to the open position, thethird link slides between the two substantially vertical members 22 a ofthe support frame 22 along a longitudinal axis of the two substantiallyvertical members.

In the particular embodiment shown in FIG. 5, the keyboard tray 23 isslidably connected to the support frame 22 by providing the supportframe 22 with a pair of slots 26 and providing the keyboard tray 23 witha pair of pegs 27. Each slot 26 is configured for receiving and guidinga corresponding peg 27 to a location along the slot that supports theportable electronic device 10 in a substantially upright position at adesired viewing angle. In some embodiments, the slots 26 may havenotches for providing a finite number of viewing angles. In otherembodiments, the slots 26 may be configured to provide an infinitenumber of viewing angles within its range of motion. In yet otherembodiments, the slots 26 may only provide one fixed viewing angle whenthe easel is in the open position. Other means for slidably connectingthe keyboard tray 23 to the support frame 22 may be used in otherembodiments.

Together, the slots 26 and the second pair of axial hinges 25 allow thekeyboard tray 23 to be selectively positioned at an angle with respectto the retaining frame 21. According to one embodiment, the angle may beselected from a group consisting of about 0° (in the closed position) toabout 45° (in the fully opened position). According to anotherembodiment, the angle may be selected from a group consisting of about0° (in the closed position) to about 25° (in the fully opened position).According to yet another embodiment, the angle may be a fixed angle, oneexample of which may be approximately 25°. The range of motion providedby the slots 26 and the second pair of axial hinges 25 preferablyenables the detachable easel 20 to present the keyboard module 30 to theuser in a way that enables the user to grasp and extract the keyboardmodule in an ergonomic manner when the easel is in the open position, asshown in FIG. 7. When the detachable easel 20 is closed, the detachableeasel 20, keyboard module 30 and portable electronic device 10 appearsubstantially as one monolithic device.

When the detachable easel 20 is closed, the easel also retains andaligns the keyboard module 30 in a precise position that enables anelectrical connection between the keyboard and the portable electronicdevice to exist. When the easel is opened to place the portableelectronic device 10 in an upright position and/or to access thekeyboard module 30, the electrical connection between the keyboard andthe device is automatically disengaged. Further description of this isprovided below.

FIGS. 8-9 illustrate examples of electrical signals that may becommunicated between the portable electronic device 10 and the keyboardmodule 30 when properly stowed in the detachable easel 20 andmagnetically connected to the back surface 12 of the portable electronicdevice. In particular, FIG. 8 is a block diagram of various circuitrythat may be included within the portable electronic device 10 and thewireless keyboard module 30. FIG. 9 is a flow chart diagram illustratinghow a charging signal may be supplied from the portable electronicdevice 10 to the keyboard module 30, and a pairing protocol may beinitiated, upon physically connecting the wired connector 36 of thekeyboard module 30 to the wired connectors 16 of the portable electronicdevice 10. FIGS. 8-9 are described below in the context of the preferredembodiment, in which a wireless keyboard module 30 is stowed on the backof a tablet 10. However, similar circuitry and methods may be used whenstowing a wireless keyboard module onto other portable electronicdevices.

According to one embodiment, a method for charging a wireless keyboardmodule 30 and pairing the wireless keyboard module to a tablet 10 maygenerally begin by physically and electrically connecting a wiredconnector 36 of the wireless keyboard module to a wired connector 16located on a back surface 12 of the tablet. In some embodiments, awireless keyboard module 30 may be retained on a back surface 12 of thetablet 10 by stowing the keyboard module within a keyboard tray 23 of adetachable easel 20, which is magnetically attached to the back surfaceof the tablet, as discussed above. As noted above, the detachable easel20 may be generally configured to retain the wireless keyboard module 30on the back surface of the tablet 10 when the detachable easel is in theclosed position. The detachable easel 20 may also be configured to alignand help engage a wired connector 36 on a front surface of the keyboardmodule 30 with a corresponding wired connector 16 on a back surface 12of the tablet 10 when the detachable easel is in the closed position.Although such an easel is preferred, one skilled in the art wouldunderstand how a wireless keyboard module 30 may be charged and pairedwith a tablet 10 without the aid of such an easel. The detachable easel20 is, therefore, preferred but not required to perform the method stepsrecited herein.

When the keyboard module 30 is retained on the back surface 12 of thetablet 10 (step 70, FIG. 9), a wired connector 36 of the keyboard module30 is physically and electrically connected to a corresponding wiredconnector 16 of the tablet 10. The wired connectors 36/16 may comprisesubstantially any type of wired connectors, such as POGO pin connectorsor pinless connectors, as discussed above. When a physical andelectrical connection is made between wired connectors 36/16, a keyboarddocked (KB Docked#) signal is asserted (step 72, FIG. 9) at wiredconnector 16 and supplied to the EC interface 50 of tablet 10, which inturn, causes a charging signal (e.g., a +5V signal) to be supplied tothe keyboard module 30 (step 74, FIG. 9) via switch 54 and wiredconnectors 16/36. Once received, the charging signal is applied to acharging circuit 38 (step 76, FIG. 9) of the keyboard module 30, whichuses the signal to charge a battery 40 and supply a DC voltage (+VBAT)to a DC/DC transformer 42. The DC/DC transformer 42 down converts the DCvoltage to a lower voltage (e.g., +3V), which is used by the keyboardmicrocontroller and RF circuitry 44.

The ability to charge a wireless keyboard module 30 via a chargingsignal supplied from a portable electronic device (e.g., a tablet) 10represents a distinct advantage over conventional designs, which requirethe user to carry around an AC adapter module and find an 110V outlet tocharge the keyboard module. Although some embodiments of the inventionmay use an AC adapter module as an additional means to charge thekeyboard, the ability to charge the keyboard through the tablet is anespecially convenient option.

In addition to a charging signal, a pairing process is initiated to pairthe wireless keyboard 30 with the tablet 10 upon connecting the wiredconnectors 36/16. For example, upon receiving the lower voltage (e.g.,+3V) from the DC/DC transformer 42, the keyboard microcontroller 44 maypower up and complete a power-on-self-test (POST) (step 78, FIG. 9), andwrite to a register to either assert or deassert a general purpose I/O(GPIO) pin assigned to a keyboard ready signal, KB_Ready# (steps 80 and82, FIG. 9). If the KB_Ready# signal is not asserted by the keyboardmicrocontroller 44 (No branch of step 84, FIG. 9), the tablet maycontinue to provide the 5V charging signal to the keyboard (step 74,FIG. 9) until the keyboard is fully charged, or at least has enoughbattery power to function at a minimum threshold level. When theKB_Ready# is asserted by the keyboard microcontroller 44 (Yes branch ofstep 84, FIG. 9), the KB_Ready# signal is transmitted from the keyboardmicrocontroller 44 to the tablet firmware 52 via the GPIO pins of thewired connectors 36/16. Upon receiving an asserted KB_Ready# signal, thetablet firmware 52 reduces the RF power of the RF circuitry to a pairinglevel (step 86, FIG. 9) and enters a pairing mode (step 88, FIG. 9) bywriting to a register to assert a Connect signal (steps 90 and 92, FIG.9), which is then supplied to the keyboard module 30 via connectors16/36.

Upon receiving the Connect signal, the keyboard microcontroller 44initiates a pairing subroutine (step 94, FIG. 9) to share a digitallyencrypted pairing code with the tablet firmware 52. The digitallyencrypted pairing code is transmitted from the keyboard module 30 to thetablet 10 via the wired connectors 36/16, and thus, is very secure.Substantially any pairing protocol and encryption method may be used. Inat least one preferred embodiment, the pairing code is changed everytime the keyboard module is connected to the tablet to further increasesecurity.

If the pairing process is unsuccessful (No branch of step 96, FIG. 9),the keyboard microcontroller 44 may reinitiate the pairing subroutine(step 94, FIG. 9) by resending a new digitally encrypted pairing code tothe tablet firmware 52. In some embodiments, this process may berepeated a number of times (e.g., up to 4 times) until pairing issuccessful (in step 96, FIG. 9), or an error condition occurs. In someembodiments, a LED status light on the keyboard module 30 may signal tothe user that pairing was unsuccessful. The LED status light may alsoindicate other status information to the user. For example, the LEDstatus light may indicate to the user that the keyboard module 30 is inthe process of pairing with the tablet 10, keyboard 46 is poweringon/off, touch pad 48 is powering on/off, battery 40 level is less than15%, battery 40 level is less than 5%, battery 40 is in the process ofcharging, and/or battery 40 is fully charged.

If the pairing process is successful (Yes branch of step 96, FIG. 9),the tablet firmware 52 writes to the register to de-assert the Connectsignal (steps 98 and 100, FIG. 9), which in turn, places the keyboardmicro-controller 44 into a deep-sleep power state (step 102, FIG. 9)until the user uses the keyboard 46 or the touch pad (TP) 48 to inputdata. When the wireless keyboard 30 is in use, data may be exchanged viathe RF circuitry 44 and antenna 58 within keyboard module 30 and the RFcircuitry 52 and antenna 56 within the tablet 56. Such data exchange maybe conducted via any well-known RF communication protocol.

The primary advantage of the pairing process shown in FIGS. 8-9 is thata pairing protocol is automatically evoked upon stowing the keyboardmodule onto the back of the tablet and electrically connecting the wiredconnectors 36/16. This allows digital, encrypted pairing codes to beshared between the keyboard module and the tablet, and requires no userinteraction other than the stowage of the keyboard module onto thetablet. Since a pairing code is exchanged between the keyboard moduleand tablet upon physical contact, the pairing process is significantlymore secure than if the pairing codes were broadcast via the RFcircuitry 44/52. This process also allows a user to mix and match a poolof tablets with a pool of keyboards without any concern, since one needonly stow a keyboard module onto a tablet to pair the two devices.

It is to be understood that the forms of the invention shown anddescribed herein are to be taken as the presently preferred embodiments.Elements and materials may be substituted for those illustrated anddescribed herein, parts and processes may be reversed, and certainfeatures of the invention may be utilized independently, all as would beapparent to one skilled in the art after having the benefit of thisdescription of the invention. Changes may be made in the elementsdescribed herein without departing from the spirit and scope of theinvention as described in the following claims.

What is claimed is:
 1. A detachable easel for a portable electronicdevice, the detachable easel consisting of a 3-bar linkage mechanism,comprising: a first link configured to provide a retaining frame foradhering to and supporting a back surface of the portable electronicdevice; a second link having a distal end connected to a first distalend of the first link via a first pair of axial hinges, wherein thesecond link is configured to provide a support frame for supporting theportable electronic device at a number of different viewing angles whenthe detachable easel is in an open position; and a third link having adistal end connected to a second distal end of the first link via asecond pair of axial hinges, wherein the third link is configured toprovide a keyboard tray for stowing a wireless keyboard module.
 2. Thedetachable easel as recited in claim 1, wherein the first link comprisesone or more magnetic structures configured for aligning with andmagnetically adhering to corresponding magnetic structures on the backsurface of the portable electronic device.
 3. The detachable easel asrecited in claim 1, wherein the second link comprises one or moremagnetic structures to provide a latching force, which retains thedetachable easel in a closed position.
 4. The detachable easel asrecited in claim 1, wherein the third link is slidably connected to thesecond link for transitioning the detachable easel from a closedposition to the open position and vice versa.
 5. The detachable easel asrecited in claim 1, wherein the second link comprises two substantiallyvertical members, each coupled at one end to a different one of thefirst pair of axial hinges and coupled at another end to a substantiallyhorizontal member of the second link, which is configured for resting ona support surface when the detachable easel is in the open position. 6.The detachable easel as recited in claim 5, wherein a width of the thirdlink is less than a distance separating the two substantially verticalmembers of the second link, such that when transitioning the detachableeasel from the closed position to the open position, the third linkslides between the two substantially vertical members of the second linkalong a longitudinal axis of the two substantially vertical members. 7.The detachable easel as recited in claim 5, wherein the first linkcomprises two substantially vertical members, each coupled at one end toa different one of the first pair of axial hinges and coupled at anotherend to a substantially horizontal member of the first link, and whereinthe two substantially vertical members of the second link are configuredto align with and receive the two substantially vertical members of thefirst link when the detachable easel is in the closed position.
 8. Thedetachable easel as recited in claim 7, wherein the two substantiallyvertical members of the first link comprise one or more magneticstructures configured for aligning with and magnetically adhering tocorresponding magnetic structures on the back surface of the portableelectronic device, and wherein the two substantially vertical members ofthe second link comprise one or more magnetic structures configured forproviding a latching force, which retains the detachable easel in theclosed position.
 9. The detachable easel as recited in claim 8, whereinthe magnetic structures on the two substantially vertical members of thesecond link are aligned with and configured to receive correspondingmagnetic structures on the two substantially vertical members of thefirst link.
 10. The detachable easel as recited in claim 1, wherein thesecond link comprises a pair of slots, wherein each slot is configuredfor receiving and guiding a peg connected to the third link to alocation along the slot that supports the portable electronic device ina substantially upright position at a desired viewing angle.
 11. Thedetachable easel as recited in claim 10, wherein the pair of slots eachhave notches for providing a finite number of viewing angles.
 12. Thedetachable easel as recited in claim 10, wherein the pair of slots isconfigured to provide an infinite number of viewing angles within arange of motion.
 13. The detachable easel as recited in claim 10,wherein the second pair of axial hinges and the pair of slots allow thethird link to be selectively positioned at an angle with respect to thefirst link, wherein the angle is selected from a group consisting ofabout 0° to about 45°.
 14. The detachable easel as recited in claim 13,wherein the angle is selected from a group consisting of about 0° toabout 25°.